fn fold_mac(&mut self, _mac: Mac) -> Mac {
panic!("fold_mac disabled by default");
- // NB: see note about macros above.
+ // N.B., see note about macros above.
// if you really want a folder that
// works on macros, use this
// definition in your trait impl:
/// apply folder to elements of interpolated nodes
//
-// NB: this can occur only when applying a fold to partially expanded code, where
+// N.B., this can occur only when applying a fold to partially expanded code, where
// parsed pieces have gotten implanted ito *other* macro invocations. This is relevant
// for macro hygiene, but possibly not elsewhere.
//